US1673157A - Compressor for refrigerating apparatus - Google Patents

Description

June '12, 1928.

D. POWELL coMPREssoR oRRE-FRIGERMQG APPARATUS 4 Sheets-Sheet l June 12, 1928 D. POWELL COMPRESSOR FOR REFRIOERATINO APPARATUS Filed April 4,(54632511/6 4 sheets-sheet 2 w ||1| Al A W A ALUMNO! June l2, 1928.

D. POWELL COMPRESSOR FOR REFRlGERATING APPARATUS 4l Sheets-Sheet 3 Filed April 4, 1925 QQQQQQQUE Ratented June 12, 1928.

`uNrrED STATES DAVVI'D POWELL, OF CHICAGO, ILLINOIS.

COMPRESSOR FOR REFRIGERATING APPARATUS.

Application led April 4, 1923. Serial No. 629,793.

My invention relates to a compressor for refrigerating apparatus particularly of the compression type wherein a liquetiable gas such as ammonia is mechanically compressed for cooling or refrigerating purposes. I consider the several features of my invention to be useful in any apparatus of the type mentioned but they are particularly useful in the ,small units intended for use in connection With domestic refrigerators.

One of the objects of my invention is the -provision of acompressor for refrigerating apparatus which will be of simple. and compact construction, inexpensive to man-ufacture, reliable in operation, which may be readily installed in connection with a refrigerator box, operated economically, and which will require but a minimum of attention.

A further object of my invention is the provision of a machine for compressing the refrigerant which will operate substantially noiselessly. It is essential that the refrigerant be compressed to a relatively high pressure. .Heretofora the valve which controls the How of the high-pressure refrigerant from the compressor cylinder .has been so constructed that` upon the piston commencing its return or nonvvorking stroke, it has been slammed down against its seat and this has been the cause of considerable noise. `My invention aims to provide a valve so constructed that it will be cushioned by a quantity of the high-pressure refrigerant being trapped under it and thus 'prevent it from violently striking its seat. Notwithstanding the use of several rings on the piston of the compressor, the high-pressure refrigerant does tend to leak around the .piston and pass into the crank case of 'the compressor. Theoil in the crank case, being churned by the crank shaft and the connecting rod, upon becoming contaminated by the refrigerant, begins to foam and thus a pressure builds up in the crank case causing the crank shaft, connecting rod and piston to knock, which not' only creates considerable noise but seriously affects proper lubrication of the parts and necessitates frequent filling of the crank case with oil.v My vinvention also aims, therefore, to provide means whereby these conditions Will be obvia'ted, preferably by providing a passageway for the refrigerant to escape from the crank case to' the low-pressure portion of the refrigerant circulatory system.

It is essential, of course, that the piston and the cylinder Walls of the compressor be kept wel] lubricated While the compressor is operating`v and, as the refrigerant comes into contact with the lubricated cylinder Walls when being compressed, it absorbs atleast some of the oil. ff the oil in the refrigerant is not removed before the refrigerant passes into the expansion coil, said coil becomes insulated by the oil depositing on the inner surface thereof and the. eiiiciency of the apparatus is reduced materially. It is a, further object of my invention, therefore, to provide novel means for separating the oil from' the high-pressure refrigerant before it passes into the expansion coil, said means preferably comprising a chamber in which a plurality of inverted spaced coneshaped screens of fine mesh are disposed for collecting the oil present in the refrigerant as the latter vflows upwardly. through the screens.

It is a further object of my invention to provide means for returning the oil separated from the refrigerant to the crank case of the compressorv so that it may again be used for lubricating purposes, this object preferably being accomplished automatically and without permitting the high-pressure refrigerant to HOW into the crank case. I preferably attain these results by providing valvecontrolled means for the oil to How from the chamber containing the oil separator to the crank case, the valve being operated by a piston located in another chamber through which the refrigerant passes, the

arrangement being such that, when the pres' sure of the refrigerant exceeds a predeter- 'mined point, it may circulate freely through the refrigerant circulatory system, said valve in that case being closed but, when the pressure of the refrigerant drops below a predetermined point, the How of the refrigerant into the 'oil separator ischecked, the valve in said latter case being opened.

lThe invention consists in the novel conico' structions, arrangements and devicesl to be hereinafter described and claimed for carrying out the above stated objects and such other objects as will appear from the following description of certain preferred embodi ments illustrated in the accompanying drawings, Wherein- Fig. 1' isv a side elevational view of an apparatus embodying the principles of my invention, certain parts being broken away to show the internal construction; y

Fig. `2 1s a view taken on the line 2f-2 of 1, the motor having been removed;

garatus, looking from-a point to the left of igs. 1 and 2, certain parts being broken away; l

Fig. 4 is also a side elevational view of the apparatus` with certain parts broken away, .looking from a point to the right of the compressor shown in Figs. 1 and 2;

;. the ines 7--7 26 and 27 Fig. 5 is a sectional View, on the enlarged scale, taken on the linel 5-5 of Fig. 2;

Fig. 6 isa sectionalview taken on' the line 6-6 of Fig. 5.

Fi s. 7 and 8 are sectional views taken on and 8-8, respectively, of Fia 3;

Fig.- 9 is a perspective view of the spring lemployed for holding the crank shaft against longitudinal movement;

Fig. 10 is a perspective View of a portion of the packin leakage aroun the crank shaft of gas and oil from the crank case;

Fig. 11 is a sectional view, on an enlarged scale, taken on the `line 11-11 of Fig. 2;

Fig; 12 is a sectional view, on an enlarged scale, taken on the line 12--12 of Fig. 11;

Fig. 13 is a side elevational view of the Vmechanism employed for controlling the iniow of water-to the condenser; an

, Fig. 14 lis a sectional view taken on the lline 14-14 of Fig. 13.

vLike characters of reference designate like parts in the several views.

Referring now to the drawings and first to Fig. 1, Iit will be seen that the apparatus com rises a com ressor 17 a condensm coil 18, an expansion valve 19 and an expansion coil 20 preferably laced in a brine tank 21 located in the re rigerator box, only the top wall 22 of the box being shown. The wall 22 is provided with an o ening 23 in which the lower portion of a ta ing the condensmg coil is placed, said tank lpreferably bei-ng built into the base' of the compressor and provided with a flange 25 t0 rest upon the wall 22.

The compressor 1s prov1ded with cylinders tively, connected by rods to a crank s aft.- 31 journaled in bearings in the 'crank c'ase 32 all of which may be of'anydesiredconstruction. Each cylinder is provided with a head 33 and the compressor is provided with a head 34 which is hollowed out on its under side so as to provide a chamber 35 extending over the cylinder heads. The discharge end of the expansion coil 20 is fitted into the lower end of a passageway 36 rovided in one wall of the tank 24. -The cy inder block of the compressor is provided with passageig.. 3. is a side elevational view ofthe ap-A ringemployed to prevent 24 containaving pistons 28 and? 29, res cterminating a short distance above the bottom of the recess. The cylinder head is provided with ports 41 to establish communication between the recess 38 and the ,cyl-- inder. An inverted cup-shaped valve member 42 slides in the lower end of the bushing and is provided with an outwardly, circumferentially extending iiange 43. A compression spring 44V interposed between the under side of the valve-member 42 and the bottom ofthe recess 38 normally holds the valve member with the upper surface of its flange seating against the lower end of the bushing.

.The outlet valve arrangement includes a plug 45 which is threaded into the `recess 39 and is provided with a recesso46 in its under side. `Ports 47 are provided in the cylinder head to establish communication between -the recess 39 and the cylinder. 'Aninverted cup-shaped valve member 48 is slidable in the recess 46 in the plug and is provided with an. outwardly, circumferentially extending a'nge 49 to cover the ports 47. A compression sprin 50 is coiled about the valve member 48, being interposed between the under side of theplug and the upper side of the.

ila-nge '49 to hold'thevalve normally closed.

vA'chamber 51, see Figs. 2, 4, 5, 6, 8 and 11, is preferably provided in the cylinder block,' passageways 52 also being provided s'o that the compressed' refrigerant may discharge through the respective outlet valves, the respective passageways 52 and into the chamber 51. l

The means for relieving excessive pressure-of thel refrigerant will now be described. The compressor head 34 is provided with a -recess 53, see Figs. 4, 5.and '11, the bottom of which is formed so as'to provide a seat 54, a port 55 being provided to establish communication between the chamber51 and.` the recess 53. A. valve member 56 is placed in the recess 53 andthe top of said recess is closed by a screw plug 57. A. compression s ring 58 is interposed between the under side of the plug 57 and the upper side of the valve 56 to hold? the valve rnormally tight against the seat 54. The compressor head is provided with a'passageway 59 toestablish communication between tlieprecess 53 and the .chamber 35. Y

A chamber 60, see Figs. 2, 3 and 5,: is prefv @muy provided in the cylinder block in which the means for separating the oil from A the refrigerant is located, the cylinder block also being provided with a passageway 61 leading from the chamber 51 to the chamber 60. `The cylinder block is provided with passageways 62, best shown in Fig. 3, leading-from the chamber 60 to a passageway 63 provided in one wall of the condenser tank, the inlet end of the condensing coil' end of said pipe being connectedto the eX- pansion valve v19. I The means for separating the oil present. in` the. refrigerant preferably comprises a plurality of inverted cone-shaped screens 67 of fine mesh which are mounted on a stem or rod 68. The passageway 61 leads into the chamber 60 at a point considerably above the bottom thereof so that the oil collected on the under sides of the 'screens 67 may drip and deposit in the bottom of the chamber without interfering withthe infiow of the refrigerant.

The cylinder block is provided with a passageway 69, see. Figs. 5 and 6, leading from the lower portion of the chamber' 60 into a chamber 70, and a passageway 71 leads from the bottom of the chamber into the crank case of the compressor so that the oil may fiow from the chamber containing the oil separator into the crank case. A valve 72 is provided in the chamber 7() for controlling the passage of oil from the chamber 6() to the crank case, said valve oscillating about a shaft 73 and being provided with a port 74. A piston 75 is placed in the chamber 51 and is connected to the valve 72 by a rod 76, said piston being responsive to the pressure of the refrigerant in' said chamber. AThe under side of, the piston is provided with a pocket 77 in which a. compression spring 78 is placed, the lower end'of said spring resting on the bottom of the chamber 51. The parts are so arranged that, when the piston 75 is pressed downby the highpressure refrigerant in the. chamber. 51, the mouth of the passageway 61 is "uncovered and the valve member 72 is moved counterclockwise in Fig. 6 and the mouth of the lpassageway 71 is closed; but, when the prersure of the refrigerant drops sufficiently, the spring 78 pushes the piston upwardly, closing the mouth of the passageway 61 and pulling the valve 72 around in a clockwise direction in said Fig. 6 to bring the port 74 into registry with the passageway 71.

In order to permit the refrigerant which leaks past the pistons into the cylinders and in the valve casing the crank case to escape therefrom, the cyllinder block is provided with a passageway shaft from the crank case will now be described. One side of the crank case .is provided with a. cap 80, see Fig. 3, which fits over the adjacent end of the crank shaft so that the escape of oil antigas around the crank shaft at that side 1s effectively prevented. The other end of the crankshaft extends through a fitting 81secured to the other side of the crank case, said fitting being provided with an inwardly, circumferentially extending flange 82 fitting around the crank shaft. That end of the crank shaft is provided with a shoulder 83. A yieldable, metallic, resilient packing ring 84, S-shaped in cross section, see also Fig. 10, is placed on the crank shaft, being interposed between the shoulder 83 and the inner face of the flange 82. A wearing washer 85 is preferably provided on the crank shaft at cach side of the packing ring. A- pulley 86 is mounted on the last mentioned end of the crank shaft. The opposite end of the crank shaft is recessed to provide a seat for a ball 87. A thrust spring member 88, see Fig. 9, is positioned within the cap 80 and carries a member 89 to provide a seat for the ball 87. The spring 88 thrusts the shaft in a direction to compress the packing ring 84.

One wall of the tank 24 is provided with a passageway 9.0, see Fig. 1, through which the water may enter the condenser tank. The water circulates through the tank around the condensing coil and passes from the tank through passageways 91, see also Fig. 4, and discharges into a chamber 92' which surrounds the compressor cylinders, being formed by the jacket of the compressor. A baffle member 93 is preferably provided in the chamber 92 and is so arranged with respect to the discharge end of the passagelio Way 91 that the water is given a whirling I motion around the compressor cylinders.

l'he water discharges from the chamber 92 through an overflow pipe 94 connected with passageways 95 which discharge into a pipe 96, see Fig. 2, leading to a drain.

Admission of water to the condenser tank is controlled b p y ally by the re erence numeral 97, see Figs'. 1, 2, 13 and 14. The water flows' from .a pipe 98, connected with any source of supply, and passes into a chamber 99 provided g, a seat 100 being provided therein for a valve 101. The valve a valve, designated gener springs 50.

side of the motor casing.

nuts 119 on th'e rod the distance bet-Ween the casing is also provided with a chamber 102 which connects with the passageway 90 leading to the condenser tank. A compression spring 103 normally holds the valve.101 closed. v

The means for automatically controlling the operation of the valve 97 includes a' casing 104y provided with a chamber 105 across which a diaphragm .106 extends. The chamber 105 connects with. a passage- Way-107 leading to one of the passageways 65 which in turn is connected With the discharge end of the condenser coil. The diaphragm is connected to a slidable stem 108 which bears against one end of a pivoted lever 109, the other` end of said lever bearing against the outer end of a slidable vstein 110 connected with the valve 101. An adjustable member 111 bears against the lever 109,

motor and compressor shafts may be varied and thus the belt may be tightened. y

Operation: The refrigerant in a gaseous state is drawn from the expansion coil 20 through the low-pressureport-ion of the system, namely, the passageways 36 and 37,

chambers 35, bushings 40, inlet valves, recesses 38, ports 41 and into the vcompi'essor cylinders, during the suction stroke of the pistons. On the return stroke of the pistons, the gaseous refrigerant is compressed, the outlet valves being'forced off their respective seats against the tension of the The` compressed refrigerant passes through the high-pressure portion o the system, namely, the recesses 39, passage ways 52, chamber 51, passageway 61, oil separator in the chamber 60, passageways 62 and 63, and into the condensing coil 18. The temperatuie of the compressed refrigerant is then substantiallythat of the cooling agent in the condenser tank. The refrigerant liquefies and discharges into the passageways 64. and 65 'and is then forced into the pipe 66, through the expansionvalve 19 and into the expansion coil 20. The expansion valve is of any ordinary construction and has a pressure reducing opening, and, as the refrigerant passes through this opening, a great reduction in pressure takes place. ant, consequently evaporates, resulting 1n a considerable reduction in temperature of the refrigerating medium and, therefore, the` Levanta'y The refriger-` heat present in the brine, or other vfluidor air surrounding the expansion coil, is eX- tracted. Fl/he vapo'i` is then returned to the compressor and the process is repeated con-` tinuously so long as the apparatus -is in operation. A

` lVhen the apparatus ceasesto operate, the pressure ofthe refrigerant in the hi h-pressure portion of the system which also includes the passageways 65 and 107 and chamber 105, goes down and equalizes with that ofv the refrigerant in the low-pressure portion of the system. Under such conditions, the spring 112 moves the'lever 109 away from the stein 11,0 andthe spring 103 holds the valve 101 closed and, therefore, the coolingy .agent does not, circulate through the con-- denser tank and the chamber surrounding the 'compressor cylinders. However, when the apparatus is in operation and the pressure of the refrigerant in the high-pressure portion of the system is relatively high, the pressure of the refrigerant against the diaphragm 106 forces it to move the lever 109 in a direction to unseat the valve 101. Thereupon, Waterfflows from the pipe 98, through , chambers 99 and 102, passageway 90 and into the condenser'tank where it circulates around the condensing coil and passes out through the passageways 91, into the chamber 92, overflow pipe 94passageways 95 and the outlet pipe 96. It will be observed, therefore, that the flow of the coolingagent through the condenser tank is ent in the Water cannot interfere with the operation of the diaphragm and` its` associated parts.

The bottom of the condenser tank being located in the yrefrigerator box, thev efficiency f of the condenser is high because the cooling agent and the condensing coil are subject to the cold air in the box.

If the pressure of the refrigerant in tlle high-pressure portion of the system should buildup to too great an extent the relief valve 56 automatically opens and establishes direct communication between the high and l low-pressure portions of the system.

,l At the end of each compression stroke of pressure refrigerant, in the' eventit Should leak around the pistons and `get into the crank case, to escape from the crank case and pass into the low-pressure portion of the the piston 28 the mouth of the passageway 79 is uncovered which permits the high-- to a minimum, aids in maintaining efficient lubrication of the Working parts, and prevents any knocking ofthe pistons, connecting rods and the crank shaft which would occur if back pressure developed, nevertheless the oil in the crank case is not permitted to escape therefrom.

The outlet valves of the cylinders operate substantially noiselessly because the compressed refrigerant Hows under the Avalve members 48 as well as around them, consequently, the pressure under and around the valve members is equalized and they seat quietly. y

It will be observed that the various passageways for the refrigerant and the Water pasing to and from the compressor and the condenser are drilled in the walls of the compressor and the condenser tank. The opportunity for leakage to occur is thus reduced to a minimum and a very compact construction 1s obtained.

The 011 separator effectively removes substantially all the oil present in the compressed refrigerant and the oil thus obtained is returned to the crank case by means entirely automatic in its operation. When the apparatus is in operation, the pressure of the refrigerant in the chamber 5l forces the piston down' thus causing the valve 72 to close the mouth of' the passagewa 71 which prevents the refrigerant from orcing the oil from the chamber 60 into the crank case and the refrigerant from passing into the crank case. However, when the apparatus ceases to operate and the pressure of the refrigerant in the high-pressure portion drops sufficiently, the spring 78 pushes the piston up thereby closing the vmouth of the passageway 61 and positioning the valve .72 with its port 74 in register with the mouth of the passageway 7l so that the oil may How under some pressure into the crank case.

I do not intend to limit my invention to the details of construction shown and described,.except only in'so far as certain of the appended claims are specifically so limited, as it Will be obvious that modifications may be made Wthout departing from the principles of the invention.

I claim: I l. The combination of oil se arating means, a chamber, a compressor En' compressing a refrigerant through said means vand chamber, means providing a passage- Way for returning the oil from said separating means to the crank case of the compressor, a valve in said passageway, a piston .in said chamber connected with said valve for closing the same, and means, operable upon therefrigerant dropping to a predetermined point, for causing said piston to open said valve.

2. The combinationv of oil separating viding a passageway for returning the oil from said separating means to the crank case of' the compressor, and means for opening said first named passageway and closing saidA second'named passageway. or for closing said first named passageway and opening said secondnamed passageway.

3. They combination of' oil separating means, a chamber, means providing a passageway lfrom said chamber to said separating means, a compressor for compressing a refrigerant through said chamber, passageway and separating means, means providing a passageway for returning the oil from said separating -means tothe crank case of' the compressor, and means in said chamber which operates, when the pressure of' the refrigerant in said chamber exceeds a predetermined point, to open said first named passageway and to close said second named passageway and, lwhen the pressure of the refrigerant in said chamberndrops below a predetermined point, to close said first named passagewayI and to open said second named passage.

4. The combination of' oil separating means, a chamber, means providing a pasconnected with said valve, said iston operating, when the pressure of' the 're rigerant in said chamber exceeds a predetermined point, to open said rst named passageway and to close said valve, and, when the pressure of the refrigerant in said chamber drops below a predetermined point, to close said first named passageway and to open said valve.

5. The combination. of oil separating means, a chamber, means providing a passageway from said chamber to said separatin means, 'a compressor for compressing a re rigerant through said chamber, passageway and separating means, means providing a'passageway for returning the oil from said separating means to the crank case of the compressor, a Ivalve. in said last named passageway, a piston in said chamber and connectedwith said valve, said piston operating, when the pressure of the refrigerant in -said chamber exceeds a predetermined point, to open said first named passageway and to close said valve, and means, operable upon the refrigerant dropping to a predetermined point, for causing said pist0n to close said first named passageway and to open said valve.

6., In the refrigerant circulatory system of a refrigerating apparatus including a low v pressure portion and a high pressure por-v tion, the combination of a compressor for compressing and circulating a refrigerant though said system, and means providing a passageway leading from one o the cylinders of the compressor to the lowpressure portion of said system, the mouth of said passageway being so located that it is uncovered only when the piston in said cylinder is at substantially the end of its comn pression stroke.

7. The combination of a compressor for compressing a refrigerant, means, for separating from said refrigerant oil which may be present therein, means providing a passageway leading rom` said oil separating means to the crank case of the compressor, and 'means actuated by the pressure of the refrigerant for wiping and closing said pas-v sagewa when the pressure reaches a predetermined strength.

8.l The combination of a compressor for compressing a refri erant, means for separating, from said re rigerant oil which lmay be present therein, means providing a passageway leading from said oil separating means to the crank caseof the compressor, means movable across the end of lsaid passageway for cleaning .and closing it, and -means controlled by the pressure of the refrigerant for operating said movable means.- 9.-The combination of ay compressor for Levanta'` compressing a refrigerant, means for separating from said refrigerant oil which may be present therein, means providing a passageway leading from said oil separating means to the crank case of the compressor, slidably mounted means adapted to move across the end of said passageway for cleaning and closing it, a p1ston adjacent to said slidable means, a-spring opposing the movement of the piston in one direction, and- `a refrigerant circulatory system, the combination of a compressor for delivering the refrigerant into the high pressure portion of said system', a crank for operating the compressor, means serving normally to exclude the refrigerant from the crank case, and means acting automatically at intervals to open-communication between the crank case and the low pressure portion of'said system.

DAVID POWELL;

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